Despite the fact that prostate cancer (PCa) continues to be the second leading cause of cancer-related death among Hispanic (H) and African American (AA) men, participation of these ethnic minorities in quality of life (QoL) outcome research is often minimal with Hs being significantly underrepresented. Ethnic minority men with PCa have less educational and financial resources at diagnosis, more indicators of disease burden (e.g., more advanced disease, higher prostate specific antigen [PSA]), and reduced QoL and survival following treatment even after controlling for sociodemographic and disease variables. Furthermore, PCa mortality rates among AAs are twice as high as in non-Hispanic white (NHW) men. Although limited by small samples, available studies indicate that there are differential outcomes by ethnicity with minority men consistently reporting lower QoL (e.g., reduced physical functioning and more disease-specific decrements such as urinary/bowel and sexual dysfunction), lower treatment satisfaction and poorer recovery after treatment;however, the mechanisms by which ethnicity may impact QoL remain to be explored. These prior studies are also lacking in a multidimensional conceptualization of ethnicity, as well as a theoretical framework that links ethnicity to health outcomes. This revised application consists of a 5-year prospective observational study designed to assess the effect of ethnic group membership on general and disease- specific QoL outcomes and disease status (i.e., PSA) in men diagnosed and treated for PCa. We will recruit 690 ethnically diverse men (230 NHW;230 H;230 AA) at diagnosis for PCa and conduct psychosocial and physical health assessments at baseline (pre-treatment), at 3-months post-treatment, and every 6 months over a 24-month post-treatment follow-up period. Our Specific Aims are to determine over a 24-month follow-up: (Aim 1) whether the relationship between ethnic group membership and (a) general (i.e., physical and mental health functioning) and disease-specific quality of life (QoL), and (b) disease status (i.e., PSA) is explained by PCa knowledge and attitudes, psychosocial resources (i.e., optimism, social support, coping and family environment), adherence to treatment and access to health care over a two-year follow-up period in men treated for PCa;(Aim 2) whether specific components of ethnicity (i.e., cultural values [e.g., familism, religiosity, cancer fatalism], ethnic identity, acculturation, minority status &SES) are associated with PCa knowledge and attitudes, psychosocial resources, access to health care &adherence to treatment over a two-year follow-up period in men treated for PCa;and (Aim 3) whether the relationship between specific components of ethnic group membership, and QoL and disease status are explained by PCa knowledge and attitudes, psychosocial resources, access to health care &adherence to treatment over a two-year follow-up period in men treated for PCa. To investigate if there are ethnic differences in baseline scores and the trajectory of change in QoL over time and the potential determinants of these differences (e.g., components of ethnicity, psychosocial resources), latent growth curve modeling in the framework of structural equation modeling will be performed. We will also test the relationships among components of ethnic group membership, postulated mediators of QoL and disease status, and their joint effects, while incorporating relevant socio-demographic and medical factors in the hypothesized models.